Short message service, which was first introduced by European wireless network operators in 1991, enables mobile subscribers to easily send and receive text messages via wireless handsets. As convergence of wireless communication networks and Internet data networks has increased, the sending and receiving of SMS messages via computer terminals has also become commonplace. Although specifications and industry standards related to SMS are constantly evolving and being modified, SMS messages have traditionally been used to convey readable text information, where the text can includes any combination of alphanumeric characters. After the initial text messaging application, service providers began focusing on using SMS as a means for eliminating alphanumeric pagers by permitting two-way, general purpose messaging and notification services. One early example of SMS service was voice mail notification service. In voice mail notification service, users are sent text messages using short message service to notify the users of the presence of voice mail messages. As technology and networks continued to mature, a variety of services were introduced, including electronic mail (email) and fax integration, paging integration, interactive banking, and information services, such as stock quotes, news highlights, etc.
SMS delivery service provides a mechanism for transmitting “short” messages to and from SMS capable terminals (e.g., wireless handsets, personal digital assistants, personal computers, etc. ) via the signaling component of the wireless communication network. With particular regard to the sending and receiving of SMS messages by a wireless handset, a wireless network provides the transport facilities necessary to communicate short messages between a short message service center (SMSC) and a wireless handset. An SMSC acts as a store and forward platform for short messages. In contrast to earlier text message transmission services, such as alphanumeric paging, SMS technology is designed to provide guaranteed delivery of an SMS message to a destination. That is, if a temporary network failure prohibits the immediate delivery of an SMS message, then the short message is stored in the network (i.e., stored at an SMSC) until the destination becomes available. Another of the key and distinguishing characteristics of SMS service with respect to previously available message communication services is that an active mobile handset is able to transmit or receive a short message at any time, regardless of whether or not a voice or data call is in progress.
SMS can be characterized as an out-of-band packet delivery technique with low per-message bandwidth requirements. Hence, SMS services are appealing to network owners and operators.
FIG. 1 is a network diagram illustrating an SMS implementation in a global system for mobile communication (GSM) wireless network. It will be appreciated that a functionally similar SMS architecture could also be employed in non-GSM wireless networks, such as American National Standards Institute 41 (ANSI-41) wireless networks. In any event, FIG. 1 includes a wireless communication network, generally indicated by reference numeral 100. Wireless network 100 is comprised of a number of components including a sending mobile terminal 110 that formulates and sends SMS message and a base transceiver station 112 base station controller 113 pair that are collectively referred to as a base station system (BSS). A base station system manages the network-to-air interface and reliably transmits SMS messages into the core wireless network. In this particular example, the receiving end of the network includes a base station system 126 and a receiving mobile terminal 128, both of which are functionally similar to the corresponding components on the sending side. Wireless network 100 also includes a pair of mobile switching centers (MSCs) 114 and 124, a pair of signal transfer points (STPs) 116 and 122, a short message service center  118 and a home location register (HLR) 120.
As mentioned above, SMSC 118 is responsible for relaying, storing, and forwarding short messages between sending and receiving SMS terminals. HLR 120 is a database platform used for permanent storage and management of mobile service subscriptions, mobile subscriber profiles, and mobile subscriber location information. HLR databases store information about subscribers that belong to the same network as the HLR. A database element known as a visitor location register (VLR) is used to temporarily store information about subscribers who are currently roaming in the area serviced by that VLR. The VLR may belong to the subscriber's home network or to a foreign network. Typically, VLR databases are integrated within MSC network elements, and, as such, a stand-alone VLR node is not shown in FIG. 1. The HLR and VLR store information needed to correctly route voice calls or data communications to the mobile subscriber. This information may include an international mobile station identification (IMSI), a mobile identification number (MIN), a mobile directory number (MDN), and/or a mobile station ISDN number (MSISDN), as well as the IDs of the VLR and MSC with which the subscriber is currently associated.
With particular regard to short message service operations, HLR 120 provides SMSC 118 with network routing information for the receiving mobile subscriber or mobile terminal 128. In certain cases, HLR 120 may also inform SMSC 118 that a mobile station is now recognized by the mobile network to be accessible after unsuccessful short message delivery attempts to the mobile station.
MSC 114 is sometimes referred to as an SMS inter-working MSC (SMS-IWMSC) because it is capable of receiving a short message from a wireless network and transmitting the short message to the appropriate SMSC. In practice, SMS-IWMSC nodes are typically integrated with the SMSCs. In a similar manner, MSC 124 is sometimes referred to as an SMS gateway MSC (SMS-GMSC) because it is capable of receiving a short message from an SMSC, interrogating a home location register for routing information, and delivering the short message to the visited MSC of the recipient mobile station.
Within the Internet domain, email servers may communicate email-originated SMS messages to an SMSC serving subscribers in a wireless communication network. As such, an SMS message may be generated by a wireline computer terminal residing within a data network (e.g., the Internet) and sent to a mobile terminal within a wireless network, and vice versa.
The core signaling infrastructure of wireless network 100 is based on signaling system no. 7 (SS7), a telecommunications industry standard signaling protocol. A detailed discussion of SS7 signaling message types and their associated functions can be found in Signaling System #7 by Travis Russell, McGraw-Hill Publishing, 1998. Additionally, a detailed discussion of SS7-related signaling within a GSM network can be found in The GSM System for Mobile Communications by Michel Mouly and Marie-Bernadette Pautet, Cell & Sys, 1992.
SMS service makes use of the SS7 signaling connection control part (SCCP) and mobile application part (MAP) protocols. Depending upon the particular implementation, SMS service may also utilize the transaction capabilities application part (TCAP) component of the SS7 protocol. With regard to TCAP-based SMS service, both American and international standards bodies have defined a MAP layer using the services of the SS7 TCAP component. The American standard is published by Telecommunication Industry Association and is referred to as ANSI-41, while the international standard is defined by the European Telecommunication Standards Institute and is referred to as GSM MAP.
FIG. 2 is a message flow diagram associated with the sending of a short message (SM) by a mobile subscriber in a GSM wireless network. In step 1, a short message, such as a text message, is originated by sending mobile station 110 and transmitted to base station controller 113. The message used to communicate the short message from sending mobile station 110 to base station controller 113 is a short message relay protocol data (SM-RP-DATA) message contained within a short message control protocol data (SM-CP-DATA) message. In step 2, BSC 113 delivers the CP-DATA message to MSC 114 over an interface referred to as the A-interface. In mobile communications networks, the A-interface is the interface between the BSC and the MSC. In response to receiving the CP-DATA message, MSC 114 formulates a ForwardMOShortMessage message and routes the message to the appropriate short message service center (SMSC) node 118, as indicated in step 3. Upon receiving the ForwardMOShortMessage message, SMSC 118 generates an SM-RP-ACK containing ForwardMOShortMessageResponse message which is routed back to originating MSC 114 (step 4). In response to receiving the ForwardMOShortMessageResponse message, MSC 114 places the SM-RP-ACK component within an SM-CP-DATA message and transmits the message via the A-interface link to originating BSC 113 (step 5) BSC 113 subsequently notifies the originating mobile subscriber that the SMS message was sent (step 6).
As the popularity of SMS messaging increases among wireless (and Internet) subscribers, the amount of wireless signaling traffic that traverses the core mobile signaling network will also increase, given the fact that SMS information is currently communicated via the SS7 signaling component of the wireless network instead of the voice or bearer path. From a bandwidth or signaling resource perspective, SMS traffic competes with other mobile signaling traffic, such as call-setup or location management-related messaging. Such SMS-related increases in the volume of signaling traffic leads to signaling congestion at a variety of signaling points in the mobile signaling network, particularly at mobile switching center nodes.
Conventional solutions to dealing with increased SMS traffic are commonly referred to as SMS-offloading techniques because these techniques off-load SMS traffic from the core signaling network to a data network. However, these conventional solutions do not address increased SMS traffic at MSCs because these solutions only offload SMS traffic downstream from the MSCs. In light of all of the call setup, teardown, and other functions performed by MSCs, there exists a long-felt need for methods and systems for reducing SMS traffic at the MSCs.